Well, "best" is difficult to say, because for each child the best curriculum might be different than the best curriculum for his brother or sister.
I can tell you what I use, and give you the reasons why I like it.
We use Time4Learning interactive high school. I like it because it is completely online, my child can access it from anywhere she has a computer and internet access. There is no huge upfront fee, just reasonable monthly payments. The program keeps the records, and has sortable reports, so if I wanted to see what lessons my daughter did in math, I could pull a record to print that gave me just that information. Their high school curriculum just started last school year, but I like the format and had used Time4Learning for elementary and middle school. My daughter likes it because she controls the pace, she gets to choose what 4 courses to take at one time, the lessons are colorful and interactive. She is a visual learner and it is a great choice for her.
I hope that you find the perfect curriculum for your family. Happy homeschooling!